Pulsed lasers conventionally used for range finding purposes such as on current main battle tanks operate on the principle of estimating range as a function of the time taken for a pulsed laser beam aimed at a target, usually via an optical sight, to reach the target and be reflected therefrom back to a reflected laser beam radiation receiver on the range finder to actuate an associated range distance indicator. These laser beams conveniently are produced by a ruby laser and generally have a very short pulsed duration and high power output over an effective distance of up to 10 kilometers.
Current main battle tanks fitted with such pulsed laser range finders generally operate with what is known as Integrated Fire Control System (IFCS). Basically IFCS means that a main armament firing sequence on the tank is controlled by a ballistics/main armament lead angle computer linked to the laser range finder, the primary optical gun sight and the armament movement controls such that once a target has been selected visually in the gun sight by the gunner it is ranged on by the laser range finder and the armament automatically brought to bear for the correct range and deflection, by the computer. It is only necessary then for the gunner to fire the armament on completion of the automatic gun laying sequence. However if the gunner does not fire in a very short time from completion of the gun laying sequence, either by design or by error, the computer disengages and the whole gun laying sequence must be carried out again before the armament can be fired. Thus the operation of a tank armament fitted with IFCS is a highly skilled matter requiring considerable practice as slow operation can be a matter of life or death to the tank crew.
Unfortunately it is difficult to practice operate a tank armament fitted with IFCS either on a live firing range or on a conventional tank gunnery training simulator. This is because the short pulse duration, high power output and long range capabilities of the laser beam in the laser range finder means that a viewer of the beam may not see the beam when fired, and thus be able to turn away, before permanent eye damage has been inflicted. Live range training facilities which allow use of the laser range finder with complete safety are few and far between with the result that live firing practice using the full IFCS system and tank armament is difficult to carry out often enough to ensure adequate training. Hence recourse has been had to a tank gunnery training simulator for training purposes.
However conventional tank gunnery training systems operate by providing a dummy tank turret coupled to a screen on which a moving target image is projected from a film for simulated engagement by the dummy turret armament. Such a system has the drawback that it does not operate with the actual tank armament, does not simulate operation of the laser range finder and thus cannot give training on the IFCS system which requires the essential use of the laser range finder to operate. Attempts have been made to alleviate these drawbacks by providing a more sophisticated tank gunnery training system such as that described and claimed in UK patent application No. 8004200 (published under the number 2 047 856A) in the name of Brian Thomas Brooksby, which allows use with the actual tank armament. Nevertheless even the latter tank gunnery training system does not permit use of the laser range finder facility and thus cannot provide crew training on the IFCS system other than in a degraded mode in which the laser range finder is inoperable, or at best replaced by a simulated range signal read off the tank gunnery training simulator and inputted manually on the tank range indicator. This means that the primary optical sight and ballistic/lead angle computer cannot be used in conjunction with the laser range finder and the tank gunner can only use the optical sight reticle and target range estimation or optical sight and the simulated range signal inputted into the computer.
The basic problem of use of the laser range finder is the problem of safety, which not only inhibits training use of the laser range finder and of an IFCS tank fitted with the laser range finder, but which inhibits safe and effective testing of the operating efficiency of the laser range finder itself. Safe testing of the laser range finder is particularly desirable to avoid going into combat situations with a defective laser range finder on a tank thereby preventing use of the IFCS and necessitating operation of the tank armament in a degraded mode.